I'm not real sure I understand how the shipping plug in works. Do I purchase all three (fedex, ups, usps). or do I need just one!?
If my customers are ordering from me, instead of me having to pay for the shipping/handling, the cost of shipping would be included automatically in their cost at checkout?!

Sorry, if I don't understand how this works...never, used a shipping plugin before. So, please explain in detail how this process